Hi A....I have heard that teeth can shift around under the gums long before we can see them or feel them. Depending on how sensitive your child is....maybe they are uncomfortable to her every once in a while. Our doctor also said that "teething pain" can be felt into their jaw, ears, sinus depending on what teeth are coming in. You will probably learn quickly their teething pattern - my oldest would have a really drooly day, spike a little fever the next day, almost always get an ear infection on the 3rd day and on the 4th day we had teeth :) Like clockwork!
As far as a fever goes, I have 3 kiddos at home (boy who is 5, boy who is 3 and a 4 month old baby girl) and it seems that every once in a while we have the fever and no other reaa symptoms...usually 24-36 hours. They just want to lay around, not eat to much, and sleep. Our doctor told us as long as you can keep getting fluids in them not to worrk to much about the eating. Since your little one is still on formula/breast milk, as long as you are getting some in her and still having wet diapers you should be fine. Virus come and go so quickly in little ones. Good luck and I hope she feels better soon!
PS My husband and I always joke that you spend so much time wanting them to "just sleep" and when they do (from being sick) we want them to "wake up!"